Apparatus for setting pins in mine roofs

ABSTRACT

A pin-setting device includes an elongate cylinder having an open end and a closed end in which a piston is movably mounted, the pin being located in the cylinder with the pin head seating on the piston. A pair of fluid jacks are located on opposite sides of and attached to the pin cylinder. A pressure plate is carried by the pin cylinder substantially near the open end, the pressure plate overlapping the jacks and engaging the mine roof to locate the open cylinder end in the predetermined area at which the pin is to be fixed, and holding the block against the mine roof. The jacks exert pressure on the mine roof through the pressure plate and block, and clamp the open end of the pin cylinder in such position. Upon introduction of fluid into the cylinder, the piston is moved in a direction to press the pin into the mine roof under a substantially smooth pushing force.

United States Patent [191 Elders et al.

[54] APPARATUS FOR SETTING PINS IN MINE ROOFS [75} Inventors: Gerald W. Elders, Christopher;

A i Thomas E. Schneider; John R.

Alongi, both of Duquoin, all of I11.

Related US. Application Data [62] Division of Ser. No. 846,795, Aug. 1, 1969.

[52] US. Cl. 227/130, 61/45 B, 61/63, 254/29 [51] Int. Cl. B25c 5/10 [58] Field of Search 61/45 B, 63; 227/130, 9; 173/34, 35; 254/29 R, 29 A [56] References Cited UNITED STATES PATENTS 1,354,054 9/1920 Mangnall et al 173/34 X 1,596,848 8/1926 Mangnall. 254/29 R 2,209,660 7/1940 Oka 254/29 R 2,575,079 11/1951 Temple 227/9 3,060,437 10/1962 Henning et al. 227/9 3,494,018 2/1970 Helderman et al. 227/9 37 in .2 I 33 41 I I Q a so 314. l

[111 3,819,101 1 June25, 1974 3,643,542 2/1972 Elders 61/45 B FOREIGN PATENTS OR APPLICATIONS 440,932 2/1927 Germany 173/34 Primary Examiner-Dennis L. Taylor [5 7] ABSTRACT by the pin cylinder substantially near the open end,

the pressure plate overlapping the jacks and engaging the mine roof to locate the open cylinder end in the predetermined area at which the pin is to be fixed, and holding the block against the mine roof. The jacks exert pressure on the mine roof through the pressure plate and block, and clamp the open end of the pin cylinder in such position. Upon introduction of fluid into the cylinder, the piston is moved in a direction to press the pin into the mine roof under a substantially smooth pushing force.

13 Claims, 5 Drawing Figures 1 APPARATUS FOR SE'I'IING PINS IN MINE ROOFS This is a division of application Ser. No. 846,795, filed Aug. 1, 1969.

BACKGROUND OF THE INVENTION This invention relates generally to improvements in roof bolting for mines, and more particularly to an improved apparatus for setting pine in mine roofs.

In the heretofore conventional apparatus used for installing roof bolts in mine roofs, an expansion shell is located on a bolt and inserted into a drilled hole, the bolt being turned to expand the shell into gripping engagement with the hole wall. The hole is drilled to a depth until a solid roof strata is reached and the expansion shell is anchored in this roof strata. It will be understood that the roof is hung from this bolt. Thereare essentially two separate operations in installing the bolt, namely, l) drilling the hole, and (2) installing the bolt and shell in the hole and tightening the bolt under torque. The expansion shell represents the only bearing area holding the bolt in the roof.

In many instances, there are areas in a mine in which there is no sufficiently rigid roof strata in which to anchor an expansion shell. This type of installation is not successful in those areas. Moreover, in many instances, sufficient anchorage strength is not achieved because support is limited by the amount of bearing area presented by the expansion shell. The bolt does not contact the roof material. Tightening the bolt upon application of torque does not increase the holding power because it is limited by the type of material engaging the expansion shell.

The drilling of the hole in the mine roof has atendency to relieve any compressive pressures inherent between the roof strata. Roof jacks are used only when the roof condition presents a hazard to the well-being of the miners and are used to keep the rock from falling. At the present time, the greatest source of injury in a mine is caused by rock falling from the roof. In addition, a further health hazard is created by the drilling of such roof holes, in that the dust is particularly harrnful to the lungs and eyes of the miners.

In other fields of endeavor, pins have been driven into walls by hammers that applied a series of abrupt impact shock blows to the pins. This manner of driving pins is undesirable in mines because the impacts tend to disturb the otherwise stable condition of the roof strata, not only in the immediate area in which the pin is driven, but for a considerable distance in all directions, and can adversely afiect the holding power of previously driven pins.

SUMMARY OF THE INVENTICN The present apparatus for setting pins in mine roofs eliminates the need for drilling any holes in the roof, thereby eliminating any dust hazard that heretofore has been injurious to the miners, and avoiding the relief of roof pressure. Moreoventhe need for driving the pin by hammer blows is also eliminated, thereby avoiding the undesirable and potentially dangerous conditions that are caused by such impact shock. The pin is pressed into the mine roof with a substantially smooth pushing force which avoids any chipping or removal or shock disturbance of roof material. The full length of the pin contacts the material of the mine roof for greater holding power and is not limited merely by the bearing surface provided by an expansion shell. Because the pin is pushed into the mine roof upon installation, there is no torque applied to the pin. It is not necessary to find a limestone roof strata in order to provide an effective installation of the pin when placed in position. The pin, when pushed into the mine roof, creates a wedging formation of the material peripherally around and engaging the pin, whereby to enhance the holding power of the pin.

As each pin is pressed into the mine roof, a compressive pressure is exerted on the roof in the area in which the pin is located in order to force the roof strata tightly together and so that the pin will hold the strata in such condition. Such compressive pressure can be applied to the roof before insertion of the pin. and/or during insertion and/or after insertion by a pressure applied to the pin.

The apparatus for pressing the pin into the mine roof provides a much faster and safer installation and better results. Moreover, shorter pins can be used in view of the fact that the pin holds along its entire length, and there is no need for locating any particular portion of such pin at a predetermined depth in order to reach a specific roof strata. According to the standards set by the U. S. Bureau of Mines, a 6,000 lb. pull is accepted as a good result on a roof bolt. With the present apparatus for installing pins, the pins have withstood at least 12,000 lbs. of pull without any sign of disturbance.

The apparatus for installing a pin in a mine roof presses an elongate pin into the mine roof by a substantially smooth pushing force applied to the pin head, and subjects the mine roof to a compressive pressure in an area of the pin to force the roof strata tightly together so that the pin will hold the strata in such condition. The compressive pressure applied to the roof can be applied before and during the pressing of the pin into the roof and/or can be applied to the roof by the pushing force applied to the pin after it has been pressed into place.

A block is located and held against the mine roof in the area in which the pin is to be fixed, and compressive pressure can be applied to the mine roof through the block. The pin is pressed through the block and into the mine roof. It is not necessary to drill a hole in the block to permit passage of the pin as is required by the apparatus utilized previously in installing roof bolts.

The present apparatus includes a pin disposed in an open-end cylinder with the pin head engaging the internal piston, and a disposed between the mine roof and the open end of the cylinder. The cylinder is held against the block and the block is held against the mine roof. A force is applied to the block by jacks to provide the compressive pressure to the mine roof, and fluid pressure is applied to the piston to press the pin through the block and into the mine roof under the substantially smooth pushing force.

The pin that is pressed into the mine roof includes an elongate shank having a point at one end and a head at the other end, and includes a plurality of discs carried by and axially spaced along the shank, the discs and shank having a friction connection that enables slidable axial movement of the discs along the shank when the discs engage the block as the pin is pressed into and through the block and into the mine roof. The discs have an interrupted peripheral margin to provide interrupted bearing surfaces to reduce friction with the cylinder wall as the pin is pressed into place, and the discs provide bearing plates between the pin head and the block when fully installed.

The combined pin-setting device and pin used in fixing the pins in the mine roof includes an elongate cylinder having an open-end and a closed-end, and a piston movably mounted in the cylinder. A positioning attached to the cylinder locates the open-end of the cylinder-at the predetermined area of the roof, and on the cylinder introduces fluid into the cylinder at one side of the piston to move the piston and to press the pin located in the cylinder through the open-end and into the mine roof under a substantially smooth pushing force. The positioning means subjects the mine roof to the compressive pressure in the predetermined area to force the roof strata tightly together so that the pin will hold the strata in such condition. This compressive pressure can be applied by jacks extending between the mine roof and floor.

Operatively connected to the fluid means and carried by the cylinder, is a safety means that senses the position of the cylinder and prevents operation of the fluid means unless the cylinder is held securely at the predetermined area.

The piston utilized in this apparatus includes a dustcleaning ring carried by the piston at the periphery adjacent one piston side, the ring engaging and wiping the cylinder wall. Furthermore, the piston can consist of a pair of interconnected yet separable parts, one of the parts including the socket in which the pin head seats and the dust-cleaning ring. This two-part construction will enable replacement of this one piston part in case of wear with minimum expense. The jacks utilized. to apply the compressive pressure are located on opposite sides of and attached to the pin cylinder, the piston rods of such jacks extending through the jack cylinders and engaging the supporting surface. A pressure plate carried by the pin cylinder substantially near the open cylinder and overlaps the jack cylinders and engages the mine roof to locate the open cylinder end in position. Meansactuates the jacks to exert the pressure on the mine roof through the pressure plate and to clamp the open cylinder end in position. The block is disposed over the open cylinder end and over the pressure plate, and is held between the pressure plate and mine roof. The'pin passes through the block and into the mine roof as the pin is pushed by the piston.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view, partly in cross section, as taken in a vertical center plane passed through a pin-setting device;

F IG- 2 is a fragmentary, side elevational view similar to FIG. 1, but showing the pin installed;

FIG. 3 is a plan view of a guide disc carried by the P FIG. 4 is a flow diagram of the hydraulic system, and

FIG. 5 is a view of a particular pin installation.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now by characters of reference to the drawings and first to FIG. 1, it will be understood that the pin-setting device generally indicated by is located and extends between a mine roof 1 1 and the subjacent mine floor 12.

The pin-setting device 10 includes an elongate pin cylinder 13 having an open end 14 and a closed end 15. A cylinder port 16 communicates with the cylinder 13 near the closed bottom end 15 and communicates with a fluid means such as a hydraulic pump which will be described later upon further description of the parts. An air port 17 is provided in the cylinder 13 adjacent the open-end 14 to provide for the free passage of air.

Located and slidably mounted in the cylinder 13 is a piston referred to by 20, the piston 20 consisting of two interconnected, yet separable parts 21 and 22.

Formed in the upper side of piston part 21 is a downwardly tapered socket 23 that forms a pin seat. The upper side of piston part 21 is concave from its outer periphery to the socket 23 located at its center. A dustcleaning ring 24 is carried by the periphery of the upper piston part 21 closely adjacent to the upper piston side. The dust-cleaning ring 24 can be constructed of leather or similar material, and wipes the wall of pin cylinder 13 upon actuation of the piston 20 to keep the cylinder wall clear of dust or other foreign matter. The concave configuration of the upper piston side also tends to clear such dust from the cylinder wall.

As is conventional, both piston parts 21 and 22 carry a plurality of piston rings 25 that provides an effective seal between the piston 20 and the wall of pin cylinder 13. The lower side of piston part 22 is divergent upwardly so as to provide a clearance with the cylinder port 16, whereby fluid such as oil can pass therethrough even when the piston 20 is located in its lowermost position in the cylinder 13.

The piston 20 is constructed of the two parts 21 and 22 so that the piston part 21 that is subjected to the most wear, can be replaced without requiring replacement of the whole of the piston 20. This partial replacement results in substantial economy.

Attached to and carried by the lower closed end 15 of pin cylinder 13, is a mounting plate 26, the mounting plate 26 extending laterally outward from cylinder 13. Provided in the mounting plate 26 at opposite sides of the pin cylinder 13, are a pair of holes 27.

A positioning means is carried by the pin cylinder 13 for locating the open cylinder end 14 at a predetermined area of the mine roof 11. This positioning means includes a pair of hydraulic jacks referred to by 30 located at opposite sides of the pin cylinder 13. Each hydraulic jack 30 includes an elongate cylinder 31 having its lower closed end seating on the mounting plate 26 and having its upper end engaging and closed by a pressure plate 32 that is fixed to the pin cylinder 13 at the upper open cylinder ends 14. Reciprocatively mounted in each jack cylinder 31 is a piston 33 to which an elongate piston rod 34 is attached, the piston rod 34 extends through the closed bottom end of jack cylinder 31 and through. the aligned hole 27 formed in the mounting plate 26. The piston rods 34 are provided with feet 35 that seat on the mine floor 12. Each jack cylinder 31 is provided with a hydraulic port 36 at its bottom end and a hydraulic port 37 at its upper end, the hydraulic ports 36 and 37 communicating with the jack cylinder 31 at opposite sides of the piston 33.

When used, the hydraulic jacks 30 are retracted and the pin-setting device is disposed in a substantially upright position with the jack feet 35 seating on the mine floor 12. A wood block 40 is disposed on top of the pressure plate 32 overlapping the open cylinder end 14.

Upon extension of the hydraulic jacks 30, the pressure plate 32 will urge the wood block 40 against the mine roof'll and will clamp the block 40 in place at the predetermined area.

A safety means generally indicated by 41 is carried by the pin cylinder 13, and is particularly mounted to one of the hydraulic jack cylinders 31. This safety means 41 includes a switch that is operatively connected to the hydraulic system so as to prevent operation of the hydraulic system unless the switch is actuated. The switch is actuated by an elongate plunger 42 that extends upwardly through the pressure plate 32 and into engagement with the wood block 40. When the pin-setting device is located in its operable position, the plunger 42 is depressed a predetermined distance so as to actuate the switch of the safety means 41, and thereby condition the hydraulic system for operation.

The pin referred to by 43 that is to be driven by the pin-setting device into the mine roof 11, includes an elongate shank 44 having a hardened point 45 at one end and a head 46 at the opposite end that is of greater diameter than the shank 44. Formed between the pin head 46 and the shank 44 is an integral, laterally extending collar 47. Mounted on and carried by the elongate pin shank 44, are one or more discs 50. These discs 50 are press-fitted on the pin shank 44 so that they will maintain their original axial placement as the pin 43 is handled prior to being pressed into the mine roof 11. However, this frictional connection between the discs 50 and the pin shank 44 will enable the discs 50 to slide longitudinally along the pin shank 44 as each disc engages the block 40, constituting an abutment, as the pin 43 is pressed into place. When thepin 43 is fully installed, the discs 50 will be clamped between the pin collar 47 and the wood block 40 to provide a substantially solid bearing plate.

Each of the discs 50, the construction of which is best shown in FIG. 3, includes a peripheral margin 51 that is provided with a series of circumferentially spaced recesses 52. The interrupted peripheral margin 51 engages the wall of pin cylinder 13. The discs 50 retain the pin 43 in its centered position within the pin cylinder 13 and guide the pin 43 in its movement along the cylinder 13. The interrupted peripheral bearing margins 51 of the discs 50 in slidably engaging the cylinder wall, keeps the friction at a minimum.

The hydraulic system is best shown in FIG. 4. The system includes a fixed displacement, hydraulic pump 53 that is connected to a manually operated, springloaded, directional control valve 54 by lines 55 and 56. Line 55 is also connected to a pressure control valve 57 through line 58, the pressure control valve 57 communicating with the reservoir tank 60. In one position of the directional control valve 54, the pump line 56 will be placed in communication with the tank 60 through line 61. The tank 60 is also placed in communication with the inlet of hydraulic pump 53 through line 62. Accordingly, it will be understood that the hydraulic fluid can circulate under substantially no load in this one position of the directional control valve 54, as, for example, from lines 55, 56 and 61 to the tank 60, and thence from the tank 60 through line 62 to the pump 53.

v in another preselected position of the directional control valve 54, the pump line 56 is connected to the cylinder port 16 by line 63 through a variable pressure snubber 64-, a check valve 65 and a spring-loaded, manual control valve 66 constituting a safety valve. The check valve 65 enables hydraulic :flow only in the one direction from the directional valve 54 to the cylinder port 16. Another line 67 communicates with line 63 downstream of the check valve 65, and is connected to a spring-loaded, manual control valve 70. When the manual control valve 70 is operated, the hydraulic fluid will flow from the pin cylinder 13 through the cylinder port 16, into line 67 and thence to the hydraulic pump 53 through the control valve 70.

The check valve 71 is preset so that when the piston 20 reaches the bottom of pin cylinder 13, the hydraulic pump 53 can draw oil from the tank 60 through the line 62.

Another hydraulic line 72 is connected to the direc tional control valve 54 and communicates by branch lines 73 and 74 with the jack cylinder ports 36, and thereby communicating with the jack cylinders 31 at one side of the jack pistons 33. Still another hydraulic line 73 is connected to the directional control valve 54, and is connected by branch lines 76 and 77 to the jack "cylinder ports 37, thereby placing such hydraulic lines 76 and 77 in communication with the jack cylinders 31 at the opposite side of the jack pistons 33.

It is thought that the operation of the combined pinsetting device 10 and pin 43 has become fully apparent from the foregoing detailed description of parts, but for completeness of disclosure, the usage will be briefly described.

First, it will be assumed that the jacks 30 are fully retracted. This can be accomplished by manipulation of the directional control valve 54 so that the pump will be connected directly to the jack cylinder ports 37 through the hydraulic lines 55, 56, 75, 76 and 77. Hy-

draulic fluid from the opposite side of the jack pistons 33 will be returned to the tank 60 through the jack cylinder ports 36 by way of hydraulic lines 73, 74, 72, and 61. Moreover, the pin piston 21) is dropped to its lowermost position by the actuation of manual control valve 70 which allows the hydraulic fluid to flow from the pin cylinder 13 through the cylinder port 16 and thence to the pump 53 by way of hydraulic lines 63 and 67.

The pin 43 is then placed into the cylinder 13 through the open-end 14 so that the pin head 46 seats in the piston socket 23. The pin discs 50 will engage the cylinder wall and guide the pin 43 to its appropriate centered position. When the pin 43 is placed in the cylinder 13 and seated on the piston 20, the pin point will be located within the open cylinder end 14. Then, a wood block 40 is placed on top of the pressure plate 32, overlapping the open cylinder end 14. The pin-setting device 10 is located in its substantially vertical position, with the jack feet 35 seating on the mine floor 12, and the jacks 30 are extended to clamp the block 40 against the mine roof 11 at the predetermined area at which the pin 43 is to be fixed.

To actuate the jacks 30, the directional control valve 54 is manipulated to place the hydraulic line 72 in communication with the pump hydraulic line 56, thereby enabling the pump 53 to introduce hydraulic fluid into the jack cylinders 31 through the cylinder ports 36 by way of hydraulic lines 55, 56, 72, 73 and 74. At the same time, hydraulic fluid in the jack cylinders 31 at the other side of the jack pistons 33 is withdrawn through the cylinder ports 37 and returned to the tank 60 by way of hydraulic line 76, 77, 73 and 61.

A compressive pressure is applied to the mine roof 11 by the actuation of the jacks 30, the compressive pressure being applied through the pressure plate 32 and wood block 40. This compressive pressure in the area at which the pin is to be fixed, forces the roof strata tightly together and preconditions the roof for the reception of the pin 43. While this compressive pressure is being applied to the mine roof 11, the hydraulic system is actuated to press the pin 43 into the mine roof 11 by a substantially smooth pushing force applied to the pin head 46. As the pin 43 is pushed, preferably with a smooth, continuous non-impact pushing force, the pin 43 will first pierce the block 40 and then move into the mine roof 11. As the pin 43 penetrates the roof strata, there is full bearing contact of the roof material with the peripheral length of the pin 43. Moreover, the inward movement of the pin 43 will cause the roof strata to deform slightly in the direction of penetration in the immediate area contacting the roof pin 43, thereby creating a wedge formation 48 that further increases the holding power of the pin 43.

As the pin 43 is pushed into the mine roof 11, the discs 50 will guide the movement of pin 43 axially along the pin cylinder 13, the interrupted peripheral bearing margins 51 engaging the cylinder wall with little friction. The uppermost disc 50 will first engage the underside of the block 40 at the open cylinder end 14, and will then slide relatively longitudinally along the pin shank 44. The next disc 50 will then engage the first disc 50 when it reaches the open cylinder end 14 and effectively abut the block 40, and then such disc 50 will move slidably longitudinally along the pin shank 44 in a direction toward the pin head 46. When fully pressed into place, the discs 50 are clamped between the pin collar 47 and the block 40.

It is desirable to place a further compressive pressure on the roof strata of the mine roof 11 by pushing the pin head 46 with the pin piston 20, this compressive pressure being applied through the discs 50, constituting the bearing plate, and the block 40. This additional compressive pressure further conditions the roof strata by forcing the strata even more tightly together. The pin 43 will then hold the roof strata in such condition.

To actuate the pin cylinder 20 to push the pin 43 into place, the control valve 66 is actuated to place the hydraulic line 75 in communication with the hydraulic line 63, thereby enabling hydraulic fluid to flow into the bottom end of pin cylinder 13 through the cylinder port 16. After the pin has been installed, the pin piston 20 is retracted by first relieving the hydraulic pressure by closing the control valve 66 and manipulating the control valve 70 so that the hydraulic fluid in the pin cylinder 13 can pass through the cylinder port 16 and be returned to the pump 53 by way of hydraulic lines 63 and 67. Then, the jacks 30 are retracted by manipulation of-the control valve 54 so that hydraulic fluid can be introduced into the jack cylinders 31 through the cylinder ports 36 by way of hydraulic lines 72, '73 and 74 and so that hydraulic fluid can be removed from the jack cylinders 31 through the cylinder ports 37 by way of hydraulic line, 76, 77, 75 and 61. The pin-setting de- 65 vice is then conditioned for placement of another roof pin 43.

FIG. 5 illustrates a specific installation of a plurality of roof pins in a mine roof utilizing the method and apparatus previously described. In this installation, a plurality of pins 43 are pressed into place in substantially 5 vertical, spaced relation across the width of the room 80, such pin 43 being installed in the same manner as previously described. In addition to these vertical pins 43, a plurality of similar elongate pins 43A are pressed into the mine roof at an angle to the vertical and between the substantially vertical pins 43 to preclude fracture of the roof strata between the substantially vertical pins 43, the angled pins 43A being pressed by a substantially smooth pushing force applied to the pin head in a similar manner as previously described with respect to the installation of pins 43.

We claim as our invention:

1. A pin-setting device for fixing pins in a mine roof, comprising:

a. an elongate cylinder having an open end,

b. a piston movably mounted in the cylinder,

c. positioning means attached to the cylinder for 10- eating the open end of the cylinder at a predetermined area of the roof, and

(1. means on the cylinder for introducing fluid into the cylinder at one side of the piston to move the piston for pressing a pin through the open end and into a mine roof. 2. A pin-setting device for fixing pins in a mine roof as defined in claim 1, in which: e. the positioning means includes an extension means extending effectively between the mine roof and floor, and a plate for abutting the roof at the predetermined area, the extension means subjecting the mine roof through the plate to a compressive pressure in the predetermined area to force the roof strata in the predetermined area tightly together so that the pin will hold the strata in such condition.

3. A pin-setting device for fixing pins in a mine roof as defined in claim 2, in which:

f. a block is seated on the plate over the open end of the cylinder, and is located between the cylinder and mine roof, the pin piercing the block and the roof as the pin is pushed by the piston, the plate 45 pressing the block against the mine roof to subject the mine roof to the compressive pressure in the predetermined area to force the roof strata in such condition.

4. A pin-setting device for fixing pins in a mine roof as defined in claim 1, in which:

e. a safety means is operatively connected to the fluid means and is carried by the cylinder, the safety means sensing the position of the cylinder and preventing operation of the fluid means unless the cylinder is held securely at the predetermined area.

5. A pin-setting device for fixing pins in a mine roof as defined in claim 3, in which:

g. a safety means is connected to the fluid means and carried by the cylinder, and includes a member engageable with the block and depressible a predetermined distance when the cylinder is positioned and secured so as to condition the fluid means for operation.

6. A pin-setting device for fixing pins in a mine roof as defined in claim 1, in which:

e. the piston has an inwardly tapered socket in one side for seating the pin.

7. A pin-setting device for fixing pins in a mine roof as defined in claim 6, in which:

f. the socket is provided substantially in the center of the piston, and

g. the said piston side being concave from its periphery substantially to the socket for collecting dust from the cylinder wall and for assisting in seating the pin in the socket.

8. A pin-setting device for fixing pins in a mine roof as defined in claim 6, in which: 1 f. a dust-cleaning ring is carried by the piston at the periphery adjacent to said one piston side, the dust cleaning ring engaging and wiping the cylinder wall.

9. A pin-setting device for fixing pins in a mine roof 1 as defined in claim 6, in which:

f. the piston includes a pair of interconnected, yet separable parts, one of the parts having the said one side and socket, while the other part has the opposite side.

10. A pin-setting device for fixing pins in a mine roof as defined in claim 1, in which:

e. the positioning means includes two or more fluid jacks carried by the cylinder, and

f. means actuates the jacks independently so as to compensate for any irregularity in the roof or floor contour.

1]. A pin-setting device for fixing pins in a mine roof as defined in claim 1, in which:

e. the pin cylinder is closed at the opposite end,

f. the positioning means includes two or more fluid jacks, each jack having a cylinder, a piston in the cylinder and a piston rod extending through the jack cylinder and engaging the supporting surface,

g. the jack cylinders are attached to the pin cylinder,

h. a pressure plate is carried by the pin cylinder substantially near the open-end, the pressure plate overlapping the jack cylinders and engaging the mine roof to locate the open cylinder end in position, and

. means actuates the jacks to exert pressure on the mine roof through the pressure plate and to clamp the open end of the pin cylinder in position.

12. A pin-setting device for fixing pins in a mine roof as defined in claim 11, in which:

j. a block is disposed over the open end of the cylinder and over the pressure plate, the block being held between the pressure plate and mine roof, and the pin passing through the block and into the mine roof as the pin is pushed by the piston.

13. A pin-setting device for fixing pins in a mine roof as defined in claim 12, in which:

k. a safety means is operatively connected to the fluid means and is carried by one of the cylinders, the safety means including a plunger extending through the pressure plate and depressible a predetermined distance, when the pin cylinder is positioned and secured under appropriate pressure to the mine roof so as to condition the fluid means for operation. 

1. A pin-setting device for fixing pins in a mine roof, comprising: a. an elongate cylinder having an open end, b. a piston movably mounted in the cylinder, c. positioning means attached to the cylinder for locating the open end of the cylinder at a predetermined area of the roof, and d. means on the cylinder for introducing fluid into the cylinder at one side of the piston to move the piston for pressing a pin through the open end and into a mine roof.
 2. A pin-setting device for fixing pins in a mine roof as defined in claim 1, in which: e. the positioning means includes an extension means extending effectively between the mine roof and floor, and a plate for abutting the roof at the predetermined area, the extension means subjecting the mine roof through the plate to a compressive pressure in the predetermined area to force the roof strata in the predetermined area tightly together so that the pin will hold the strata in such condition.
 3. A pin-setting device for fixing pins in a mine roof as defined in claim 2, in which: f. a block is seated on the plate over the open end of the cylinder, and is located between the cylinder and mine roof, the pin piercing the block and the roof as the pin is pushed by the piston, the plate pressing the block against the mine roof to subject the mine roof to the compressive pressure in the predetermined area to force the roof strata in such condition.
 4. A pin-setting device for fixing pins in a mine roof as defined in claim 1, in which: e. a safety means is operatively connected to the fluid means and is carried by the cylinder, the safety means sensing the position of the cylinder and preventing operation of the fluid means unless the cylinder is held securely at the predetermined area.
 5. A pin-setting device for fixing pins in a mine roof as defined in claim 3, in which: g. a safety means is connected to the fluid means and carried by the cylinder, and includes a member engageable with the block and depressible a predetermined distance when the cylinder is positioned and secured so as to condition the fluid means for operation.
 6. A pin-setting device for fixing pins in a mine roof as defined in claim 1, in which: e. the piston has an inwardly tapered socket in one side for seating the pin.
 7. A pin-setting device for fixing pins in a mine roof as defined in claim 6, in which: f. the socket is provided substantially in the center of the piston, and g. the said piston side being concave from its periphery substantially to the socket for collecting dust from the cylinder wall and for assisting in seating the pin in the socket.
 8. A pin-setting device for fixing pins in a mine roof as defined in claim 6, in which: f. a dust-cleaning ring is carried by the piston at the periphery adjacent to said one piston side, the dust-cleaning ring engaging and wiping the cylinder wall.
 9. A pin-setting device for fixing pins in a mine roof as defined in claim 6, in which: f. the piston includes a pair of interconnected, yet separable parts, one of the parts having the said one side and socket, while the other part has the opposite side.
 10. A pin-setting device for fixing pins in a mine roof as defined in claim 1, in which: e. the positioning means includes two or more fluid jacks carried by the cylinder, and f. means actuates the jacks independently so as to compensate for any irregularity in the roof or floor contour.
 11. A pin-setting device for fixing pins in a mine roof as defined in claim 1, in which: e. the pin cylinder is closed at the opposite end, f. the positioning means includes two or more fluid jacks, each jack having a cylinder, a piston in the cylinder and a piston rod extending through the jack cylinder and engaging the supporting surface, g. the jack cylinders are attached to the pin cylinder, h. a pressure plate is carried by the pin cylinder substantially near the open-end, the pressure plate overlapping the jack cylinders and engaging the mine roof to locate the open cylinder end in position, and i. means actuates the jacks to exert pressure on the mine roof through the pressure plate and to clamp the open end of the pin cylinder in position.
 12. A pin-setting device for fixing pins in a mine roof as defined in claim 11, in which: j. a block is disposed over the open end of the cylinder and over the pressure plate, the block being held between the pressure plate and mine roof, and the pin passing through the block and into the mine roof as the pin is pushed by the piston.
 13. A pin-setting device for fixing pins in a mine roof as defined in claim 12, in which: k. a safety means is operatively connected to the fluid means and is carried by one of the cylinders, the safety means including a plunger extending through the pressure plate and depressible a predetermined distance, when the pin cylinder is positioned and secured under appropriate pressure to the mine roof so as to condition the fluid means for operation. 